High molecular weight polymeric dispersions with metal scavenger

Abstract

Methods for manufacturing a polymer dispersion, polymer dispersions, and their use are provided herein. The methods of manufacturing the polymer dispersion comprise the steps of providing a reaction mixture in an aqueous medium comprising a polymeric dispersant and a monomer composition comprising radically polymerizable monomers, and subjecting the monomer composition in the reaction mixture to a radical polymerization to synthesize a dispersed polymer so as to form the polymer dispersion, wherein the radical polymerization is performed in presence of a metal scavenger system comprising a metal scavenger and an acid. These polymer dispersions are designated as water-in-water (w/w) polymer dispersions.

What is claimed is: 
     
         1 . A method for manufacturing a polymer dispersion comprising the steps of
 C) providing a reaction mixture in an aqueous medium comprising
 a) a polymeric dispersant and 
 b) a monomer composition comprising radically polymerizable monomers, wherein the radically polymerizable monomers are selected from the group of one or more of a non-ionic ethylenically unsaturated monomer, a cationic ethylenically unsaturated monomer, or an amphiphilic ethylenically unsaturated monomer; 
   D) subjecting the monomer composition in the reaction mixture to a radical polymerization to synthesize a dispersed polymer and to form the polymer dispersion, wherein step B is performed in the presence of a metal scavenger system comprising an acid and a metal scavenger, which metal scavenger is a first carboxylic acid comprising 2, 3, 4, or 5 carboxylic acid groups and at least one nitrogen atom, and wherein the pH at the beginning of step B is from 4.5 to and   E) stabilizing the polymer dispersion by adding a second carboxylic acid.   
     
     
         2 . The method according to  claim 1 , wherein step C) is performed by adding the second carboxylic acid at a temperature of less than 40° C. 
     
     
         3 . The method according to  claim 1 , wherein the acid is an inorganic acid. 
     
     
         4 . The method according to  claim 1 , wherein the pH at the beginning of step B is from 4.7 to 5.1. 
     
     
         5 . The method according to  claim 1 , wherein the second carboxylic acid comprises 1, 2, or 3 carboxylic acid groups and no nitrogen atom. 
     
     
         6 . The method according to  claim 1 , wherein the radically polymerizable monomers are selected from the group of one or more of the following:
 i. a non-ionic monomer of formula (I)   
       
         
           
           
               
               
           
         
         where 
         R 1  means hydrogen or methyl; 
         R 2  and R 3  are, independently of each other, hydrogen, C 1 -C 5 -alkyl or 
         C 1 -C 5 -hydroxyalkyl, 
       
       ii. a cationic monomer of formula (II) 
       
         
           
           
               
               
           
         
         where 
         R 1  means hydrogen or methyl; 
         Z 1  is O, NH or NR 4 , wherein R 4  means C 1 -C 4 -alkyl, and 
         Y is one of 
       
       
         
           
           
               
               
           
         
         where 
         Y 0  and Y 1  are a C 1 -C 6  alkylene group, optionally substituted with one or more hydroxy groups; 
         Y2, Y3, Y5, Y6, Y7 independently of each other, are each C 1 -C 6 -alkyl; and 
         Z −  is a counterion; 
       
       iii. an amphiphilic monomer of formulae (III) or (IV) 
       
         
           
           
               
               
           
         
         where 
         Z 1  is O, NH, NR 4 , wherein R 4  means C 1 -C 4 -alkyl, 
         R 1  means hydrogen or methyl, 
         R 8  is a C 1 -C 6  alkylene group, 
         R 5  and R 6  are, independently of each other, each C 1 -C 6 -alkyl, preferably methyl, 
         R 7  is a C 8 -C 32  alkyl, optionally substituted with one or more hydroxy groups, and 
         Z −  is a counterion; or 
       
       
         
           
           
               
               
           
         
         where 
         Z 1  is O, NH, NR 4 , wherein R 4  means C 1 -C 4 -alkyl, 
         R 1  means hydrogen or methyl, 
         R 10  means hydrogen, C 8 -C 32  alkyl, C 8 -C 32  aryl and/or C 8 -C 32  aralkyl, 
         R 9  is a C 1 -C 6  alkylene group, and 
         n is an integer between 1 and 50; or 
       
       iv. an ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups. 
     
     
         7 . The method according to  claim 1 , wherein the monomer composition comprising the radically polymerizable monomers at least comprises the non-ionic monomer of formula (I) being selected from those in which R 1  means hydrogen or methyl, and R 2  and R 3  are both hydrogen, hydrogen and C1-C3 alkyl, hydrogen and hydroxyethyl, or both C 1 -C 3  alkyl, and/or the cationic monomer of formula (II) being selected from those in which R 1  means hydrogen or methyl, and Z 1  is O, NH or NR 4 , wherein R 4  means methyl, Y 1  is C 2 -C 6  alkylene, preferably ethylene or propylene, Y 5 , Y 6  and Y 7  are all methyl, and Z −  is a halogen. 
     
     
         8 . The method according to  claim 1 , wherein the monomer composition comprises at least 5 wt.-% of the non-ionic monomer of formula (I) 
       
         
           
           
               
               
           
         
         where 
         R 1  means hydrogen or methyl; 
         R 2  and R 3  are, independently of each other, hydrogen, C 1 -C 5 -alkyl or C 1 -C 5 -hydroxyalkyl; 
         at least 5 wt.-% of the cationic monomer of formula (II) 
       
       
         
           
           
               
               
           
         
         where 
         R 1  means hydrogen or methyl; 
         Z 1  is O, NH or NR 4 , wherein R 4  means C 1 -C 4 -alkyl, and 
         Y is one of 
       
       
         
           
           
               
               
           
         
         where 
         Y 0  and Y 1  are a C 1 -C 6  alkylene group, optionally substituted with one or more hydroxy groups; 
         Y2, Y3, Y5, Y6, Y7 independently of each other, are each C 1 -C 6 -alkyl; and 
         Z −  is a counterion; 
         0 to 1.25 wt.-% of the ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups; and 
         optionally, further ethylenically unsaturated monomers. 
       
     
     
         9 . The method according to  claim 1 , wherein the polymeric dispersant is a homopolymer made of the cationic monomer of formula (II) 
       
         
           
           
               
               
           
         
         where 
         R 1  means hydrogen or methyl; 
         Z 1  is O, NH or NR 4 , wherein R 4  means C 1 -C 4 -alkyl, and 
         Y is one of 
       
       
         
           
           
               
               
           
         
         where 
         Y 0  and Y 1  are a C 1 -C 6  alkylene group, optionally substituted with one or more hydroxy groups; 
         Y2, Y3, Y5, Y6, Y7 independently of each other, are each C 1 -C 6 -alkyl; and 
         Z −  is a counterion. 
       
     
     
         10 . The method according to  claim 1 , wherein the polymeric dispersant is a homopolymer made of a (meth)acryloyl amidopropyl trimethylammonium salt or a (meth)acryloyl oxyethyl trimethylammonium salt. 
     
     
         11 . The method according to  claim 1 , wherein step B) is conducted by sequentially or simultaneously adding to the reaction mixture redox initiator system comprising an oxidizing agent and a reducing agent. 
     
     
         12 . The method according to  claim 1 , wherein the ethylenically unsaturated cross-linker is a cross-linker containing 2 or 3 ethylenically unsaturated groups. 
     
     
         13 . A polymer dispersion comprising
 c) a polymeric dispersant and   d) dispersed polymer derived from a monomer composition comprising radically polymerizable monomers, wherein the radically polymerizable monomers are selected from the group of one or more of a non-ionic ethylenically unsaturated monomer, a cationic ethylenically unsaturated monomer, or an amphiphilic ethylenically unsaturated monomer;   
       wherein the polymer dispersion comprises a metal scavenger system comprising a first carboxylic acid as a metal scavenger and an inorganic acid, and wherein the polymer dispersion comprises a second carboxylic acid. 
     
     
         14 . A polymer dispersion obtained by a method for manufacturing the polymer dispersion according to  claim 1  comprising the steps of
 A) providing a reaction mixture in an aqueous medium comprising
 a) a polymeric dispersant and 
 b) a monomer composition comprising radically polymerizable monomers, wherein the radically polymerizable monomers are selected from the group of one or more of a non-ionic ethylenically unsaturated monomer, a cationic ethylenically unsaturated monomer, or an amphiphilic ethylenically unsaturated monomer; 
 
 B) subjecting the monomer composition to a radical polymerization to synthesize a dispersed polymer and to form the polymer dispersion, wherein step B is performed in presence of a metal scavenger system comprising an acid and a metal scavenger, which metal scavenger is a first carboxylic acid comprising 2, 3, 4, or 5 carboxylic acid groups and at least one nitrogen atom, and wherein the pH at the beginning of step B is from 4.5 to 5.3; and 
 C) stabilizing the polymer dispersion by adding a second carboxylic acid.